Citrus tree named ‘Nectar’

ABSTRACT

A new variety of mandarin citrus is described that is distinguished by fruit having no seeds and flowers having anthers bearing sterile pollen.

FIELD OF THE INVENTION

A new mandarin citrus tree Citrus reticulata hybrid is described. Thenew variety named ‘Nectar’ is desirable to the consumer because it hasseedless fruit and to the commercial grower because it bears lateripening (end of December to beginning of February) citrus fruits havingrich having rich flavor.

BACKGROUND OF THE NEW TREE

The present invention relates to a new and distinct variety of mandarintree Citrus reticulata hybrid developed by inventors Aliza Vardi,Pinchas Spiegel-Roy, Avraham Elchanati and Ahuva Frydman-Shani from acontrolled pollination made at the Volcani Center in Bet Dagan, Israel.

Asexual reproduction by conventional bud grafting onto Troyer reetstocknucellar seedlings of the new variety in Israel has shown that the newcharacteristics are stabilized and permanently fixed through successivepropagation.

The objective in breeding the present new tree variety, assigned thedenomination ‘Nectar’ was to obtain a late ripening citrus mandarinhaving fruit with few or no seeds. In the spring of 1979, a controlledpollination cross of ‘Wilking’ (unpatented) mandarin (Citrus reticulataBlanco) was made at the Agricultural Research Organization, The VolcaniCenter, in Bet Dagan, Israel. The fruit was collected in November 1979and seeds of the fruits were extracted and subsequently germinatedduring January 1980. About 150 seedlings were grown from the germinatedseeds. Each seedling was grafted in September 1982 onto Troyer rootstocknucellar seedlings. The grafted plants were planted in June, 1984 in theAgricultural Research Organization experimental grove, Bet Dagan,Israel. The first fruits were observed in January 1988 and observationsof the fruits were again made in 1989. One of the 140 seedlings wasdesignated 56/4. This scion was observed to be fully ripe in the lastweek in December to the end of January. The fruit of this selection wasorange in color and completely seedless.

Bud wood was taken from 56/4 and grafted in the spring of 1988 onto 6Troyer rootstock. The grafted plants were planted a year later in theexperimental grove of the Agricultural Research Organization in BetDagan. The first crop of trees was obtained in 1992. The yield of thescion grafted onto Troyer rootstock was good. The fruit was fully ripein January. The color of the ripe fruit was orange and the fruit waseasy to peel and had a very rich flavor. The juice had a sugarconcentration of about 13% and an acid concentration of about 0.9%.

SUMMARY OF THE INVENTION

Some characteristics of the new mandarin tree, designated ‘Nectar’, werecompared with its seed and pollen parent ‘Wilking’, as shown in Table 1.

TABLE 1 Chromosone Tree Fruit color Number Seeds/fruit Pollen fertility¹‘Nectar’ Orange 2n = 18 0 Sterile RHS 24A  0% ‘Wilking’ Orange RHS 2n =18 6-15 94% 24A ¹Estimated by acetocarmine staining

The following is a detailed description of the new mandarin citrusvariety based on observations made under typical Israeli groveconditions. Observations were made on 5-6 year old trees in Israel.

The tree is medium sized, about 3 to 4 meters high by 4 meters wide at5-6 years after planting. This is quite similar to ‘Wilking’. The tree'svigor is also medium with an annual terminal growth after pruning ofabout 100-110 cm in length and 10-12 mm in diameter as measured in 1993in Bet Dagan, Israel. Young shoots have no anthocyanin coloration at thetip.

The tree is quite productive with a slight tendency to alternatebearing. The canopy is moderately dense. The bark of the young shoots isinitially smooth and green gradually turning into a smooth grayed-green.

The chromosome number of the tree is diploid (2n=18) as is thechromosome number of the parents.

The leaves somewhat resemble that of ‘Wilking’ in shape and size. Foliarflushes, as measured in Bet Dagan, Israel, occur between April andSeptember. The color and veination of the leaves are quite similar tothat of ‘Wilking’. Leaf blade is quite firm and straight in crosssection. Petioles are without wings.

Flowering, as measured in Bet Dagan, Israel, in 1993 occurs between midMarch and the beginning of April. The characteristics of the floweringand the flower parts are similar to ‘Wilking’ with one exception: theanthers contain aborted pollen only. Terminal flower buds have noanthocyanin coloration. Anther color is yellow with 0-1% stainablepollen grain as obtained by staining with acetocarmine. The trees floweronce per year.

The fruit is seedless. The fruit shape is somewhat flat and it is mediumsized. When 50 fruits were measured, the fruit had an average weight of98 grams, an average height 46 mm, and an average diameter 68 mm. Thefruit surface is usually smooth with an orange color, 24A, on The RoyalHorticultural Society of London Colour Chart, and bears an averagenumber of conspicuous rind oil glands. Fruit ripening does not differfrom outside of the canopy to the inside, but the fruit color of theoutside canopy is a little brighter as compare to the fruit color of theinside canopy. There is no persistence of the style and the areola isnot completely developed. A navel is absent or very rare. The rind isthin and easy to peel. Fruit productivity of a single tree at age 7 isabout 40 kg.

The color of the albedo is yellow-orange and the flesh is orange incolor. The fruit contains 10-11 segments and is very juicy. The fruitreaches maturity in January in Israel. The ripening of the fruit on thetree and within the fruit is uniform. Fruit remaining on the tree doesnot regreen and does begin to lose quality until mid February. The fruithas attractive appearance and the fruit flavor is very rich andpleasant.

DESCRIPTION OF THE PHOTOGRAPHS

The new citrus tree is illustrated in the accompanying colorphotographs.

Sheet one depicts the whole tree and canopy shape of the new variety.

Sheet two shows the exterior of the fruit as well as transversemidsections in a plane substantially perpendicular to the axis,illustrating no seeds.

DESCRIPTION OF THE NEW TREE

The following is a detailed description of the new mandarin citrusvariety based on observations made under typical Israeli groveconditions. Color designations have been determined from The R.H.S.Colour Chart published by The Royal Horticultural Society, London.

Tree:

Origin.—Self-pollination cross of ‘Wilking’ mandarin.

Classification.—Botanical: Citrus reticulata hybrid. Common: Mandarincitrus. Cultivar: ‘Nectar’.

Shape.—Round with tendency to be upright with growth of young shoots.

Thorns.—Appear only at the juvenile stage; at the productive stage isthornless.

Branching.—Upright.

Canopy.—Moderately dense.

Trunk.—39 cm at 20 cm above the ground.

Bark.—Immature: Smooth, yellow-green, RHS 146B. Mature: Smooth,grayed-green, RHS 189A.

Leaf.—Size: Length: 92 mm, width 34.0 mm. Shape: Lanceolate and taperpointed. Leaf blade: Firm, straight in cross section. Petioles:Wingless, 12 mm length, 1.5 mm in diameter, Green RHS 147B. Foliarflushes: April-September (Israel). Color: Green RHS 147A (upper), GreenRHS 147B (lower).

Habit.—Medium vigor.

Height.—3-4 m (5-6 years).

Width.—4 m (5-6 years).

Disease resistance.—No particular susceptibility or resistance observed.

Winter hardiness.—Winter temperature in Bet Dagan, Israel averages 4-7degrees Centigrade.

Flower:

Petals.—5.

Petal color.—White RHS 155D (upper and lower).

Flowering period.—Mid March-beginning of April in Bet Dagan, Israel.

Flower drop.—April.

Stamens.—20, complete style.

Anther color.—Yellow RHS 9D.

Pollen fertility.—Aborted pollen only.

Anthocyanina coloration.—None.

Fruit:

Shape.—Slight oblate.

Size.—Medium.

Weight.—98 g (average of 50 fruits).

Height.—46 mm.

Diameter.—68 mm.

Skin color.—Orange, RHS 24A.

Rind oil gland.—Conspicuous, average number (48/cm²).

Style.—No persistence.

Navel.—Absent.

Rind.—Thin (2-3 mm) and easy to peel.

Albedo.—Yellow-orange RHS 19B.

Flesh color.—Orange RHS 25A.

Areola.—Incompletely developed.

Fruit segments.—10-11.

Time of maturity.—Date of picking_January (Israel).

Fruit extract.—(Test conducted Jan. 16, 1997). Total soluble solids(TSS): 13%. Acid content: 0.9%. TSS/acid ratio 14.4. Flavor: Richflavor.

Seeds: None.

What is claimed is:
 1. A new and distinct variety of Citrus reticulatahybrid tree substantially as herein described and shown.